Ethylene polysulfide polymer lubricant



Patented July 5, 1949 UNITED s'rArEs PATENT ornce 2,474,859 ETHYLENEPOLYSULFID 'LUBRIC Blyde A. Perkins, San Lore Rockwell Manula'cturinPa., a corporation of Pennsylvania No Drawing. Application DecemberSerial No. 637,256

I Comp ny,

E POLYMER ANT nzo, Calii'., assignor to Pittsburgh,

2 Claims. (01. zoo-cos) This invention relates to a new composition ofmatter and its preparation and is more particu-- service usually rapidlydeteriorate under such conditions and necessitate frequent replacement.

The lubrication of valves used in modern chemical industries has createda demand for a lubricant which is particularly inert with respect to awide range of solvents and corrosive fluids while maintaining requisitelubricating efllciency over a wide temperature range. The inventionprovides a lubricant which is substantially inert with respect tohydrofluoric acid and like strong corrosive fluids and substantiallyinsoluble in hydrocarbons such as butane, isobutane, butene and otherpetroleum derivatives associated with the manufacture of high octanegasoline, and mixtures of hydrofluoric acid and these hydrocarbons, andit is a major object of the invention to provide such a novel lubricantand novel methods of making it.

It is a further object of the invention to provide a novel lubricantcomprising the synthetic polymeric reaction product of a sodiumpolysulfide solution and ethylene dichloride after treatment of thatproduct under special temperature conditions for a predetermined lengthof time to produce a lubricant of desired viscosity, and the process formaking the lubricant.

A further object of the invention is to provide a novel process formaking a lubricant of suitable viscosity for use in lubricated plugvalves and which is chemically inert with respect to anhydroushydrofluoric acid and petroleum hydrocarbons, wherein a special sodiumpolysulfide solution is reacted with ethylene dichloride to produce asynthetic ethylene polysulfide polymer, and the polymer mass issubjected tospecial heat treatment for a predetermined length of time toconvert it to a form in which it is a lubricant having the aboveproperties.

Further objects of the inventionwill appear as the description proceedsin connection with the appended claims.

In practice of the invention, I prepare a special 2 sodium polysulfidesolution which is reacted with ethylene dichloride to produce asynthetic organic polymer, polymeric sodium polysulfide, and the polymermass after purification such as washing is subjected to special heattreatment to alter the viscosity of the mass until it is satisfactoryfor use as a valve lubricant and like purposes. Two examples ofprocesses for producing the invention will now be given, it beingunderstood that these are given by way of illustration only and are notdeterminative of the scope of the invention, that scope being indicatedand defined in the claims.

Example I 28.8 kilograms of sodium sulfide (sixty per cent concentratedtechnical) and 19.2 kilograms of sulfur are dissolved in 113.7 kilogramsof water at F. to give a sodium-polysulflde solution having a sodiumpolysulfide ratio of N a2S3.5 to Na2S4,o.

I then slowly and gradually add 19.2 kilograms of ethylene dichloride tothe heated sodium polysulfide solution at a rate which requires aboutforty minutes to add the ethylene dichloride, continuing agitationduring this period, and then the reaction is allowed to proceed tocompletion, this taking about fifteen minutes more.

The resultant product of the above reaction is an ethylene sulfidepolymer which is a fluid latex which is pumped into a suitable containerwhere it is coagulat'ed and precipitated by addition of 17.7 kilogramsof hydrochloric acid (20 B.) diluted five times in cold water. The acidsolution is gradually and continuously added to the latex in smallproportions until all the latex has been precipitated and the solutionhas reached a pH value between 3.5 and 4.0. The precipitate, which is anethylene polysulfide polymer, is washed with cold running water toremove impurities.

To convert this ethylene polysulfide polymer into a form suitable forlubricant purposes, I

place the washed precipitate in an oil jacketedmixer where it is heatedat about 400 F. for from one to two hours to drive ofi. volatilecomponents 3 and obtain a product of desired viscosity for lubricantpurposes.

Example II 28.8 kilograms of sodium sulfide (sixty per cent concentratedtechnical) and 19.2 kilograms of sulfur are dissolved in 118.7 kilogramsof water at 160 F. to give a sodium polysulfide solution having a sodiumpolysulfide ratio of NazSas to NazSm as in Example I. This solution isplaced directly in a steam and jacketed reactor and agitated and heatedbetween 160 F. and 170 F., the emulsification of Example I beingomitted.

I then slowly and gradually add 19.2 kilograms of ethylene dichlorideinto the reactor, at a rate requiring from two and one half to threehours to add all of the ethylene dichloride, maintaining the temperaturebetween 160 F. and 170 F. and agitating the solution during this period.The resultant reacted material is a yellowish-green mass which is arubbery and viscous ethylene polysulfide polymer. It is purified andwashed with boiling water.

Thirty pounds of this viscous rubbery mass are placed in a suitablemixer heated by an oil jacket, and the mass is heated and agitated atabout 380 F. to 400 F. for a period of about one and one half to twohours. Preferably this conversion temperature is 400 F. and maintaineduntil the mass has a viscosity of the desired degree for lubricantpurposes. This heat treatment drives off volatile components andconverts the rubbery mas-s into an ethylene polysulfide lubricant ofdesired viscosity.

It will be noted that the essential difierence between Examples I and IIis that in Example II, where the ethylene dichloride is added veryslowly, ther is no intermediate latex form which must be precipitated asin Example I. Otherwise the essential considerations are similar.

It is essential to practice of the invention that the sodium polysulfideratio in the solution be as specified in both examples, betweenNa2S:.5-and NazSao.

The conversion temperature limits for reducing the viscous polymer, theprecipitate of Example I or the rubbery mass of Example II, to lubricantof the desired viscosity must also be strictly observed, as theconversion temperature must be between approximately 380 F. and 400 F. Ihave found that heating the polymer at 3'75 F. or lower for periods upto eight hours will not produce a lubricant of satisfactory viscosity.Similarly I have found that heating the polymer at 410 F. and higherwill convert it into a hard mass not suitable for a lubricant.

The time of heating the polymer at 380 F. to 400 F. during conversion isalso critical. I have found that heating the polymer at thosetemperatures for a period of three hours or more converts it into a hardrubbery mass unsuitable for lubricant use. The time of heating duringconversion is a function of the desired viscosity, which property mustbe kept under observation during the operation. Preferably theconversion time for heating at 380 F. to 400 F. is about one and onehalf to two hours.

If desired, the lubricant end product may be blended with variousmaterials such as anthracene oil to alter its viscosity to suit specialconditions, much as extremely low climatic temperatures, withoutappreciable change in its chemical properties.

The above described synthetic ethylene polysulfide polymeric lubricantend product is completely inert with respect to petroleum hydrocarbonsand anhydrous hydrofluoric acid, so that it is especially useful as avalve lubricant in lines in chemical processes handling such materials,and its physical properties, especially its viscosity as determined byits method of manufacture, are especially satisfactory for lubricatedplug valve lubricants.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States LettersPatent is:

1. The process of preparing a synthetic ethylene polysulfide polymer ofdesired viscosity for use as a plug valve lubricant comprising reactingan aqueous sodium polysulfide solution having a sodium polysulfide ratioof NazSas to Nazsio with ethylene dichloride to produce a polymericethylene polysulfide material and heating said material at in the rangeof 380 F. to 400 F. for between one and one half to two hours to convertit into a lubricant of said desired viscosity.

2. The lubricant prepared by the process defined in claim 1.

BLYDE A. PERKINS.

REFERENCES crrEn The following referenlces are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,923,392 Patrick Aug. 22, 19331,950,744 Patrick Mar. 13, 1934 2,192,700 Turner Mar. 5, 1940 2,221,650Patrick Nov. 12, 1940 OTHER REFERENCES Martin, Ind. & Eng. Chem., Oct.1936, vol. 28, Pages 11441149.

